摘要
Our objective was to examine the potential of limit feeding that keeps a previously growing animal at a constant size (termed progressive limit feeding) to maximize profit using a 3D surface to integrate the effects of animal size, feeding rate, and time in the feedlot. The constant size contours of the surface were determined using a combination of results. We used data from a study of growing beef cattle being fed to maintain specified sizes coupled with modern growth rate data for animals fed ad libitum in a feedlot. These feed rate contours were best-fit declining exponentials. They shared the same exponent and they originated on the ad libitum curve, thus defining the entire possible growth surface. The asymptotes of these exponentials coincided with the interspecies mean for the metabolic body size of mature animals. This surface also demonstrated the phenomenon of compensatory growth. We proved that the most profitable growth path across this surface is of a particular form under realistic assumptions. Specifically, we proved that the profit maximizing growth path in the feedlot began with a period of progressive limit feeding and then allowed ad libitum feeding to the same market time as experienced by the standard continuous ad libitum fed animal. The opportunity cost of holding the progressively limit-fed animal longer in the feedlot than the animal fed ad libitum quickly overpowered any profit gained by limit feeding. Consequently the progressively limit-fed animal on the optimal feeding path at sale time was slightly smaller but potentially more profitable than the animal fed ad libitum, both slaughtered at the same time. It may also have an economically favorable body composition. Thus we have demonstrated a process for maximizing profit in the feedlot. The approach involved developing a growth surface to integrate the effects of progressive limit feeding and subsequent compensatory growth. After refinement this same process could be applied to other livestock.
摘要译文
我们的目标是研究使用3D曲面综合考虑动物大小，饲喂速度和饲养场时间的影响，使先前生长的动物保持恒定大小（称为渐进式极限饲喂）以最大化利润的潜力。使用结果的组合确定表面的恒定尺寸轮廓。我们使用了一项关于饲喂生长中的肉牛来维持指定规格的研究数据，并结合了饲养场中随意饲喂动物的现代生长率数据。这些进给速度轮廓是最佳的-拟合指数递减。它们共享相同的指数，它们起源于任意曲线，因此定义了整个可能的增长表面。这些指数的渐近线与成熟动物的代谢体大小的种间平均值一致。该表面还显示出补偿生长的现象。我们证明，在现实的假设下，该表面上最有利可图的增长路径具有特定的形式。具体来说，我们证明了饲养场中利润最大化的增长路径始于逐步限饲期，然后允许随意采食到与标准连续随意采食动物所经历的相同的上市时间。保持逐步限制的机会成本–饲养场中的动物比随意喂养的动物更长，很快超过了通过限制喂养获得的任何利润。因此，与随意宰杀的动物（同时宰杀）相比，逐步限制饲养的动物在出售时处于最佳的觅食路径上要稍小一些，但其利润可能更高。它还可能具有经济上有利的身体成分。因此，我们展示了使饲养场利润最大化的过程。该方法涉及开发生长表面，以整合渐进限饲和随后的补偿生长的影响。改进后，可以将相同的过程应用于其他牲畜。
Bruce M Hannon[1];Michael R Murphy[2]. Progressive limit feeding to maximize profit in the feedlot[J]. Journal of Animal Science, 2019,97(4): 1600-1608